Effect of forefoot type on postural stability - a cross sectional comparative study

Weight-bearing foot structure may influence postural control by either decreasing the base of support (BOS) or increasing the passive instability of the joints of the foot. Poor postural control has been implicated as the main causative factor for foot and ankle injuries. The purpose of this study was to examine the influence of forefoot postures on postural stability during single limb stance.

Sixty healthy individuals between the ages of 18 to 31 were selected using a purposive sampling procedure based on forefoot angle measurements and categorized into three groups; high forefoot varus (≥8°) (n=20), neutral forefoot varus (1°-8°) (n=20) and low forefoot varus group (≤1°) (n=20). Static foot measurements, including relaxed rearfoot angle and navicular drop, and foot dimentsions were performed. Height and weight were also recorded for all the subjects. Center of Pressure (COP) excursion in Anterior-posterior (AP) and Medial-lateral (ML) planes and Stability Index (SI) with eyes open and eyes closed conditions were also measured using the force platform.

Strong correlations were found between forefoot angle and rearfoot angle (r=0.71, p<0.01), forefoot angle and navicular drop (r=0.58, p<0.01), and between rearfoot angle and navicular drop (r=0.661, p<0.01). There were no correlations (p>0.05) between the forefoot angle and all the five COP measures, except between forefoot angle and SI with eyes closed (r= -0.25 p<0.01).

There is a significant positive correlation between forefoot angle and rearfoot angle and between forefoot angle and navicular drop. Forefoot angles did not affect the maximum AP COP and ML COP excursions or SI in healthy subjects.

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